1. Field of the Invention
The present invention relates to an electronic parts mounting apparatus and an electronic parts mounting method of mounting the electronic parts on a substrate.
2. Description of the Related Art
In the electronic parts mounting apparatus, the electronic parts are picked up by the transfer head from the parts feeding portion, in which a large number of parts feeding devices such as the tape feeder, or the like are aligned in parallel, and then transferred to the position over the substrate and mounted thereon. In recent years, in reply to the request for the improvement of work efficiency, the transfer head equipped with a plurality of suction heads is often employed as the transfer head. Such transfer head makes it possible to pick up and mount a plurality of electronic parts in one mounting turn during which the transfer head goes and comes back once between the parts feeding portion and the substrate.
At this time, if the plural parts simultaneous suction, i.e., the electronic parts are sucked by a plurality of suction nozzles in one elevating operation of the transfer head respectively, can be realized upon picking up the electronic parts from the parts supplying portion by the transfer head, an operation efficiency of the picking-up operation can be improved and also the work efficiency can be further improved. In order to make this plural parts simultaneous suction possible, a mount pitch between the suction nozzles in the transfer head must be set to coincide with an alignment pitch between the tape feeders in the parts feeding portion.
However, it is not always easy to satisfy this condition. In fact, such plural parts simultaneous suction is inhibited in many cases due to various factors such as slight difference in the above pitch, displacement caused by the system error, and so forth. Therefore, for the purpose of reducing such inhibiting factors as much as possible, various countermeasures were taken (see JP-UM-A-2-56499 and JP-A-2001-94294).
The example in Patent Literature 1 intends to get such a configuration that, if a pitch displacement value is within a predetermined range even in the situation that these pitches are slightly displaced mutually, the pitch displacement is assigned to a plurality of suction nozzles by adjusting the overall position of the transfer head in the picking-up operation. Thus, the pitch displacement assigned to the individual suction nozzles is suppressed within a tolerance. Also, the example in Patent Literature 2 is constructed such that, since mutual positions of the sliders that hold both ends of the beam onto which the transfer head is mounted are displaced to incline an angle of the beam, a nozzle alignment line connecting respective suction nozzles in the transfer head can be mate with a straight line connecting respective parts supplying positions of the parts supplying unit of the parts supplying portion.
However, in the foregoing prior arts, the correction can be realized merely to some extent in extremely limited situations such as the difference in the pitch in a certain range, the inclination of the suction nozzles or the tape feeder in the particular direction, and so on. As a result, the above prior arts cannot largely extend the target area from which plural parts can be sucked simultaneously.